Camera devices are controlling various parameters relating to their behavior during their operation. For example, during video recording or previewing for taking a still picture, the camera devices continuously measure brightness or color balance of the taken images and adjust the exposure time or white balance.
It is beneficial if such a control mechanism can react quickly on changing conditions. For example when a user moves the camera from a bright window view to a much darker indoor view, the exposure time should be made longer in order to ensure that some amount of details can still be captured.
On the other hand, there are cases where the quick adjustment makes the user uncomfortable. For example when recording a video clip, parameters like exposure time of successive image frames should not vary too much. Otherwise the brightness of images may change back and forth between lighter and darker in a short period. The result may be that the recorded video clip appears to comprise a plurality of different video clips made under different lighting conditions. In circumstances where e.g. sudden glimpses of sunlight are included in the view of steadily hold camera, too hasty changes in brightness parameter may further result in pumping effect, that is, brightness continuously changes between darker and lighter in clearly noticeable steps and never settling down.